This invention relates to large bulk containers or bins which are fashioned from multiplys of laminated materials, such as two or more plys or layers of corrugated paperboard. Large bulk containers are often formed from a generally rectangular blank, usually flat, which has been suitably scored and crushed, by foldong certain panels of the blank and then joining the ends of the blank to form a flattened tube structure. After the formation of the blank into a collapsed tube by joining its opposite ends, the packager or final user of the bulk bin then unfolds or erects the flattened tube structure into its expanded, tubular condition or configuration, to thereby form a bulk bin of generally rectangular configuration.
Along those portions of the bulk bin which are to be folded 180 degrees (often termed a reverse fold) in passing from the original, planar blank to the collapsed or knocked down tube, there is, in prior art bulk bins of this type, a distortion and build-up of the paperboard material at these vertically extending edges of the bulk bin, where the 180 degree folds become 90 degree folds or edges upon refolding 90 degrees attendant set-up or erection. The strength of the erected container is diminished by this irregular bulging or distortion and the appearance of the container at these folds is also marred.